Nano-sized Ag2CO3 and carbon nanotube (CNT) composites were fabricated by a facile chemical precipitation approach in N,N-dimethylformamide (DMF) solvent. The as-prepared Ag2CO3/CNT samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and ultra violet-visible (UV-Vis) diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the samples was evaluated by photocatalytic degradation of methyl orange (MO) under visible light irradiation. The results showed that the nano-sizedAg2CO3 particles and CNTs were well combined. The Ag2CO3/CNT composite with CNT content of 1.5%(w) exhibited optimal photocatalytic activity under visible light. Ninetythree percent of the MO was removed by the Ag2CO3/CNT composite within 60 min. For the Ag2CO3/CNT composites, we found that the incorporation of CNT improved the structural stability of Ag2CO3 compared with Ag2CO3. After three cycles, 81% of the MO was decomposed by the Ag2CO3/CNT composite with CNT content of 1.5% (w), but only 59.5% of the MO could be removed by Ag2CO3. The improvements in the activity and stability are attributed to the conductive structure supported by CNTs, which favors electron-hole separation and the removal of photogenerated electrons from the decorated Ag2CO3.